Amaigamator



N. S. KEITH AMALGAMATOR May 3, 1927.

Filed April 21. 1924 3 Sh'eets-Sheat l {N VEN TOR.

l LPWVII.

1 L @L 1 E B E1 K Fig I.

WITNESSES.

- 1,627,! May 3, 1927. I N. s. KEITH 81 AMALGMATOH Fil'ed April 21. 1924a Sheets-Sheet 2 WITNEsJES: I INVEN OR: asim. W 4/722? Patented May 3,1927.

UNITED STATES 1,627,181 PATENT OFFICE.

NATHANIEL SHEPARD KEITH, F PHILADELPHIA, PENNSYLVANIA; CLAUDE L. ROTH,ADMINISTRATOR OF THE SAID NATHANIEL SHEPARD KEITH, DECEASED.

. AMALGAMATOR.

My invention relates to improvements in I added either during or after amilling, grind ing or concentration process.

Although amalgamators of a revolvable type have been used with somesuccess in the treatment of pulverized ores, the con ditions under whichmost of them operate cause the mercury to be broken up and oxidized withthe result that much mercury is lost, especially when pressure is usedin addition to the force of gravity to pass the metalliferous pulpthrough a large mass of mercury. Furthermore, the precious metals insuch ores are often in such fine particles or so flattened that theytend to float over the amalgamating surface iwithout coming in .contactwith same or the metallic particles are so rusty or coated withimpurities that they will not amalgamate' readily.

The object of my invention is to provide a machine and process whereby alarge quantity of metalliferous pulp, to which mercury has been added,can be rapidly and cheaply brought into contact with an extensiveamalgamating surface, by means of centrifugal force in the presence ofnascent hydrogen, produced by electrolysis of he water, without usingany pressure except 'centrifugal force and the force of gravity to passthe pulp over said surface so that the machine will have greatercapacity and efficiency with less loss of mercury than other machines incommon use.

I attain said object by applying said forces and an electrical currentto such pulp containing mercury by meansof a novel apparatus, the chieffeatures of which are a rotatable, vertical shaft carryingconcentrically a disc having a boss around said shaft; a hollow,vertical cylinder held to i said disc by said boss and by compression ofa cap holding the top of said cylinder rigidly to said shaft; a tube oflead. covering said cylinder but insulated therefrom and from said discand cap: encircling said tube. an annular cup bolted to said disc butelevated. therefrom by adjustable washers; a reniov able verticalcylinder with an inner surface of copper and a serrated bottom restingin said cup and guyc'd to said disc and an insulated ring near the topof said shaft connected by conducting wire with said tube of lead andmeans for rotating said as a unit and supplying pulp containing mercuryto the annular space between said cylinders and passing an electricalcurrent to said ring and taking it up from said outer cylinder when saidpulp is passing through the machine. The electrical current is used toproduce nascent hydrogen at the amalgamating surface to preserve thebrightness and receptive properties of the mercury. The apparatus ismade operative by means of other devices combined with said fundamentalfeatures which I will now describe by explaining the construction andmanner of using a simple form of machine embodying my invention andreferring to the accompanying drawings illustrating the same in whichlike letters of reference are used to denote like parts of theapparatus, except as otherwise noted. 1 Figure 1 represents a verticalsectional view of the rotating arts of such machine and its bearings,wit out showing the lat eral supports or electrical connections.

Figure 2 is a view in which the lower parts of the cylinder and cup arerelatively displaced, the former being shown in elevation, and thelatter being shown in crosssection and illustrates the manner in whichthe bottom of said cylinder must be serrated to allow any excess ofmercury or amalgam on the inner surface of said cylinderto be caught insaid cup, which could not be as readily shown in Figure 1 withoutcausing confusion in the lines thereof.

Figure 3 represents a plan view and Figure 4 a vertical view 'on anenlarged scale of the lower portions of the outer and inner cylindersand the annular cup and the disc by which they are supportedrespectively and the bolts and springs for keeping the outer cylinder inplace while being rotated with the other parts aforesaid. Figure 4 alsoshows how the tube of lead surrounding the inner cylinder must beinsulated therefrom and from said disc.

Figure 5 represents a top view of such machine when supported by aframework not shown in the previous figures without showing the clampand wires needed for electrical corniection.

Figure ti represents a broken vertical section of the upper and lowerportions of the machine when set in such a framework, not

parts including certain parts shown in Figure-4 or the bearin beneaththe disc shown in Figure 1 whic bearing is to be supported by arms likethe one shown beneath the pulley in Figure 6, bolted to a cross-barextending to uprights at equal distances from the centre line of theshaft. This figure shows also the manner of making the electricalconnections and introducing the pulp.

In all the figures, A represents a rotatable vertical shaft, preferablyof steel, to be revolved in' bearings at the top, bottom andintermediate points marked with the letters B, B, B, B respectively asshown in Figure 1. The top bearing must be removab e and should be madewith arms like a spider to be bolted to the upright supports of an outerframe shown in Figures 5 and 6 only. The intermediate bearings are notessential to the working ofthe machine except for the purpose ofrelieving strains on ot er parts and decreasing any tendency tooscillation. The shaft and all parts atfixed thereto may be turned atany desired speed by means of a pulley C fastened on said shaft anddriven by a belt connected with a suitable source of power not shown.The bearing B at the bottom of the shaft must be set in a solid basefrom which vertical supports must be extended to projections of the topbearing B as shown inFigure 6. All bearings should be provided withbushings which are not always shown in the drawings.

D refers to the circular disc aforesaid, preferably made of metal, whichmust be fastened concentrically to the shaft A and is intended tosupport at some distance above it the concentric annular cup E throughthe medium of washers L, preferably of insulating material, throughwhich are passed bolt-s K so as to leave spaces Z as outlets for thepulp to flow from the machine which outflow may be regulated byinserting or removing washers, but said outlets must not be increased tosuch an extent that the machine cannot be kept filled with pulp whenrotated at a speed which would otherwise insure amalgamation.

F refers to a copper cylinder supported, concentrically in a verticalposition by the annular cup E in which the bottom of said .cylinderrests at a sufficient distance from same therefrom, whicliinay be donemore frequently than the cleaning up of the amalgamating surface of saidcylinder without much interruption to operations.

said shaft must be threaded for some distance above said cap as shown inFigure 6.

P refers to a tube or covering of lead to be placed around the cylinderM except at the ends thereof, at such distance from said cylinder andsaid ends as will permit suflicient insulating material, such as meltedasphalt, to be introduced between said lead and said cylinder and themetals adjacent to the end thereof to prevent any passage of electricalcurrent from said lead as an anode to the outer cylinder F 18 a cathodein an electrical circuit except through the pulp as an electrolyte. Theword, insulation is used in some of the figures to mark the space to beleft'for that purpose.

R refers to a removable ring ortwo-piece clamp to be atlixed to theshaft A but insulated therefrom and to be connected with electricconducting wires with the lead tube or casing P'to make the latter ananode when a carbon electric brush connected with the positive pole of asource of electricity is caused to bear against the periphery of 'saidring or clamp while another such brush connected with the negative poleis caused to bear against the outside or upper edge of the outercylinder F in such a manner that its inner surface of copper will act asa cathode in an electrolytic circuit, during the operation of theapparatus.

G denotes the springs for holding the outer cylinder F in place by meansof stay bolts H on said cylinder and like bolts I on said disc D.

S refers to upright parts of the framework supporting the working partsof the apparatus and T to cross bars for holding the intermediatebearings B, B. firmly in position and U to angle irons for joining theupright supports to the'base of the machine.

X is a chute or launder for introducing the pulp in an obvious mannerand Z refers to the spaces between the disc D and cup E divided by saidbolted washers L through which itmust flow out of the machine.

To operate the machine it is first started rotating and then a stream ofpulp is allowed to flow in the annular space between the two revolvingcylinders F and M until said space is practically filled with pulp afterwhich the pulp must not be allowed .to flow in faster than it isdischarged from f-themachine through the outlet space Z,

which can be regulated as aforesaid to conform to the speed of rotationmost suitable for amalgamation.

It is obvious that the revolving parts of the machine must be rotated atsufiicient speed to make the centrifugal force of their movement operateto bring the mercury and metals to be recovered from the pulp in contactwith the copper amalgamating surface before the force of gravity takessuch material through the machine and persons skilled in the art ofamalgamating can readily determine what speed is necessary by observingthe effect on said surface.

The amount of mercury added to the pulp should be kept as low aspossible without impairing the eliiciency of the machine. A quantityequal to three times the weight of precious metal in the ore should besufficient, that is to say for each ounce of gold to the ton of ore inthe pulp three ounces of mercury should be added thereto in the launderX, if not introduced in a previous operation. As the pulp in whichminute particles of precious metal are suspended or floating passesbetween said cylinders. each particle is impelled through the pulp bythe centrifugal force of rotationtoward the copper amalgamating surfaceproportionately to its specific gravity with respect to other particlesand the mercury being the most liquid and dense will most rapidly reachsaid sur face and having the property of forming an amalgam with copperwill adhere thereto and absorb the particles of other metals impelledagainst such surface if they are capable of being amalgamated or wettedby the mercury. Particles which will not amalgamat-e will be displacedby the swirling action of the pulp and carried out of the machine.Mercury which remains liquid will tend to pass down said surface intothe annular cup E while mercury accumulating precious metals will adhereto the amalgamating surface in a gradually hardenii'ig coat which mustbe removed by cleaning up from time to time as the aflinity of themercury for precious metals is satisfied.

To clean up, first stop the flow of pulp and allow thepulp in themachine to run out. Then stop'the machine and remove the topmost bearingB by lifting itoff the shaft and detach the electrical brushes from thering- R and cylinder F. Then free the cylinder F by releasing thesprings (i and remove said cylinder. To save time in operating. a likecylinder may be put in its place and the said bearing and electricalconnections replaced without waiting for the cylinder carrying amalgamto be cleaned in the manner well known to the art.

It will be'manii'est to those skilled in mechanics, after understandingmy invention, that modifications and substitutions of equivalents may bemade in the manner of forming and operating an apparatus of the kindIhavc described without departing from the spirit or scope of myinvention and that it is not to be limited to the particular apparatusdescribed.

While the relative positions and dimensions of the various parts of anapparatus intended to apply my process may vary somewhat from thoseindicated by my drawings, I should say that in order to be effectivethere must be no change that will destroy the function for which I havedesigned any such parts and that the space between the two cylindersshould not be less than one-tenth or more than three-tenths of thediameter of the outer cylinder and that the height of the cylindersshould not be less than said diameter or exceed four times the same forobvious reasons.

I claim as my invention 1. In an amalgamating machine, the combinationconsisting of a rotatable, vertical shaft carrying concentrically a dischaving a boss around said shaft; a hollow, vertical cylinder held tosaid disc by said boss and by compression of a cap holding the top ofCal said cylinder rigidly to said shaft; a tube of lead covering saidcylinder, but insulated therefrom and from said disc and cap; en-

circling said tube, an annular cup bolted to said disc but elevatedtherefrom by adjustable washers; a removable vertical cylin= der with aninner surface of copper and a serrated bottom resting in said on andguyed to said disc and an'lnsulat-e ring near the top of said shaftconnected by conducting wire with said tube of lead and means forrotating said parts as a unit and supplying pulp containing mercury tothe annular space between said cylinders and passing an electricalcurrent to said ring and taking it up fromsaid outer cylinder when saidpulp is passing through the machine. I

2. In an amalgamating machine, the com: bination of a rotatable,vertical shaft a disc carried thereby, a verticall arranged innercylinder carried by said of lead surrounding said cylinder, a com isc,atube its pression cap for holding said'inner cylinder ri idl tosaidshaft, an outer, c lindrical cover of copper with a-serrated bottomedge which cover surrounds said cylinder, a memher having an annularrecess secured upon said disc and within which recess said serrated edgeis positioned, an insulated ring carried by said shaft, an electricalconductor between said covering of lead and said ring, means forsupplying pulp containing mercury to' said outer cylinder, means forrotating said'shaft, and means for passing an electrical current to saidring and taking up said current from said outer cylinder.

3. In an amalgamating machine, the combination of a rotatable, verticalshaft, 2. disc carried thereby, a vertically arranged inner cylindercarried by said disc, a tube of lead surrounding said. cylinder, acompression cap for holding said inner cylinder rigidly to said shaft,an outer cylindrical cover of copper with a serrated bottom edge whichcover surrounds said cylinder, means for resiliently securing the lowerpart of said outer cylinder to said disc, a member having an annularrecess secured upon said disc and within which recess said serrated edgeis positioned, an insulated ring carried by said shaft, an electricalconductor between carried thereby, a verticallyarranged inner cylindercarried'by said disc, a tube of lead surrounding said cylinder, acompression cap for holding said inner cylinder rigidly to said shaft,an outer cylindrical cover of copper with a serrated bottom edge whichcover surrounds said cylinder, a member having an annular recess securedupon said disc and within which recess said serrated .edge ispositioned, an insulated ring carried by said shaft, above saidcylindrical cover and inner cylinder, an electrical conductor betweensaid covering of lead and said ring, means for supplying pulp containingmercury to said outer cylinder, means for rotating said shaft, and meansfor passing an electrical current to said ring and taking ulxsaidcurrent from said outer cylinder.

' In testimony whereof I afiix my signature.

NATHANIEL s. KEITH,

